Whenever I use a map in an area I've used a map before, the image gets corrupted. Random grey lines appear, and if that glitchy map the same as a map already placed on a wall, the wall map also becomes glitched. Furthermore, I had a wall that showed a map of my world, but many of the maps have vanished.
Did you open your world in 20w17a in the past? If so please try the steps described in MC-179858.